Liner for separating adhesive material



UNITED STATES PATENT OFFICE LINER FOR SEPARATING ADHESIVE MATERIAL NoDrawing. Application March 30, 1937,

Serial No. 133,828

2 Claims.

This invention relates to liners for separating unvulcanized rubber orsimilarly adhesive sheet material.

In the handling of sheet rubber, rubberized fabrics, and other adhesivematerials, sheets of cloth or paper are customarily used to separate theadhesive sheet material. These separating sheets are commonly known asliners. In order to reduce the expense of manufacture and transportationof adhesive plastic materials, it is desirable to provide a liner whichis low in initial cost, one which may be used repeatedly, and one whichmay be readily stripped from the adhesive sheet without injury to theliner or to the plastic sheet.

The principal objects of this invention are to provide a liner havinglow initial cost, great flexibility, low adhesive properties, and longlife.

These and other objects are attained by treating a web of cloth, paper,or other permeable material with an wens dispersion of sodium silicatecontaining suitable plasticizing agents such as glygzrige, sulfonatedoils, soaps, and waxes. The soap preferably is formed during thepreparation of thedispersion .by the combination of the oils with thealkali of the sodium silicate, but the soap may be added as aningredient. The glycerine, being hygroscopic, also prevents excessivedrying of the liner.

The waxes not only act as plastlcizing or softening agents, but alsoreduce the adhesiveness of the composition and reduce the cost thereof.

As an example of a composition which has given very satisfactoryresults, the following formula may be used:

I") C f7 (CI. 91-68) 7 r Pounds Sodium silicate solution 52 B 65Glycerine 15 Parafiln wax 15 Oleic acid 4 5 The ingredients are mixedpreferably while they are hot. The oleic acid reacts with the alkali ofthe sodium silicate to form a soap which tends to emulsify the wax. Theparaffin wax may be a low priced soft Wax. During drying of the linerthe wax melts and forms a coating over the partially dried silicate andprevents successive convolutions of the liner in a roll thereof fromsticking to each other. The parafiin wax may be replaced with sulfonatedcastor oil or similar sulfonated vegetable o Is.

In forming a liner, the sheet material, either in the form of fabric orpaper, is passed through a heated bath of the impregnating material, thematerial remaining in the bath for a sufllcient time to totally orpartially impregnate it as desired. After the excess coating materialhas been drained therefrom, the sheet material is dried and rolled uponitself.

I claim:

1. A separable liner for adhesive material, said liner comprisingpermeable sheet material impregnated with a composition of water glassmixed with giycerine, paramn wax and olelc acid.

2. The method of preparing a separable liner for adhesive material whichcomprises mizdng at an elevated temperature water glass with glycerine,paraflln wax and oleic acid, and impregnating permeable sheet materialwith the resulting composition.

WAIJI'ER R. HICKLER.

